Precerebellin, or CBLN1, is the precursor of a conserved brain-specific hexadecapeptide termed cerebellin. CBLN1 and other members of the precerebellin family also contain a C-terminal C1q signature domain that mediates trimeric assembly of atypical collagen complexes. The deduced 193-amino acid protein contains a hydrophobic N terminus followed by the cerebellin sequence. It also contains 3 potential N-glycosylation sites. Over about 145 amino acids in its C terminus, CBLN1 shares 31.3% identity with C1QB , but it lacks N-terminal collagen-like motifs. The cerebellin peptide is flanked by val-arg and glu-pro residues, suggesting that it is not liberated from precerebellin by the classical dibasic amino acid proteolytic mechanism seen in many neuropeptide precursors.